胶厚对钛合金-复合材料接头胶接性能的影响

采用钛合金与芳纶纤维复合材料制备了不同胶层厚度的单搭接接头。利用DIC与万能试验机对接头进行了拉伸-剪切性能测试,研究了不同胶层厚度异质材料的接头胶接性能、应变场与破坏模式的变化规律,分析了在拉伸载荷下,不同胶层厚度接头的失效特点。结果表明,当胶层厚度由0. 2 mm增加至1. 2 mm时,接头极限载荷由6. 13k N降低至5. 89 k N,损伤后剩余强度降低,薄胶层接头出现渐进失效;复合材料端头高剥离与拉伸应变区域面积增加,厚胶层与被胶接件一同变形,导致接头提前失效;钛合金-胶层界面破坏模式增多,芳纶纤维复合材料层间破坏模式减少;接头在发生复合材料层间破坏后,仍能够保持较高的剩余强度,当钛合金-胶层界面遭到破坏后,易整体失效。

Effect of Adhesive Layer Thickness on Bonding Performance of Titanium Alloy and Composite Joints

The single lap joints with different adhesive layer thickness were fabricated by titanium alloy and aramid fiber composites.The tensile-shear load test of joints was carried out by using DIC and universal testing machine.The influence of adhesive thickness onbonding properties,strain field and failure modes of dissimilar materialsingle lap joints were studied.The failure characteristics of joints with different adhesive thickness under tensile load were analyzed.The results showed that as the thickness of adhesive layer increased from 0.2 mm to 1.2 mm,the ultimate load of joint was reduced from 6.13 kN to 5.89 kN,and the residual strength of damaged joint decreased.The thin adhesive layer joint had progressive damage.The high peeling and tensile strain region at the end of composite adherend increased.The thick adhesive layer was deformed together with adherend,making the joint fail early.The interfacial failure between the titanium and adhesive layer increased,and the delamination failure of aramid fiber composite decreased.After the composite had delamination failure,it still maintained a high residual strength.After the interfacial failure between the titanium and adhesive layer occurred,it was easy to fail overall.